Arthritis of the knees, Osteo Arthritis (OA) degeneration of the bones, and Rheumatoid Arthritis (RA)degeneration and inflammation of the cartilage, occur as the result of chronic knee joint dysfunction or autoimmune issues respectively. Injury to the meniscus is also a very common knee joint problem. Knee OA is very common among heavy or obese people. Your knees are not designed to carry too much weight, only a normal healthy weight.
Pain and stiffness are the most common symptoms of OA. Pain, heat and swelling are the most common symptom of RA.